Embedding¶

Provides functions that map binary quadratic models and samples between a source :termgraph and a target graph.

For an introduction to minor-embedding, see Minor-Embedding.

Generators¶

Tools for finding embeddings.

Generic¶

minorminer is a heuristic tool for minor embedding: given a minor and target graph, it tries to find a mapping that embeds the minor into the target.

 minorminer.find_embedding(S, T, **params) Heuristically attempt to find a minor-embedding of a graph representing an Ising/QUBO into a target graph.

Chimera¶

Minor-embedding in Chimera-structured target graphs.

 chimera.find_clique_embedding(k, m[, n, t, …]) Find an embedding for a clique in a Chimera graph. chimera.find_biclique_embedding(a, b, m[, …]) Find an embedding for a biclique in a Chimera graph. chimera.find_grid_embedding(dim, m[, n, t]) Find an embedding for a grid in a Chimera graph.

Pegasus¶

Minor-embedding in Pegasus-structured target graphs.

 pegasus.find_clique_embedding(k[, m, …]) Find an embedding for a clique in a Pegasus graph.

Utilities¶

 embed_bqm(source_bqm, embedding, …[, …]) Embed a binary quadratic model onto a target graph. embed_ising(source_h, source_J, embedding, …) Embed an Ising problem onto a target graph. embed_qubo(source_Q, embedding, target_adjacency) Embed a QUBO onto a target graph. unembed_sampleset(target_sampleset, …[, …]) Unembed a samples set.

Diagnostics¶

 chain_break_frequency(samples_like, embedding) Determine the frequency of chain breaks in the given samples. diagnose_embedding(emb, source, target) Diagnose a minor embedding. is_valid_embedding(emb, source, target) A simple (bool) diagnostic for minor embeddings. verify_embedding(emb, source, target[, …]) A simple (exception-raising) diagnostic for minor embeddings.

Chain-Break Resolution¶

Handling samples with broken chains when unembedding.

Generators¶

 chain_breaks.discard(samples, chains) Discard broken chains. chain_breaks.majority_vote(samples, chains) Unembed samples using the most common value for broken chains. chain_breaks.weighted_random(samples, chains) Unembed samples using weighed random choice for broken chains.

Callable Objects¶

 chain_breaks.MinimizeEnergy(bqm, embedding) Unembed samples by minimizing local energy for broken chains.

Exceptions¶

 exceptions.EmbeddingError Base class for all embedding exceptions. exceptions.MissingChainError(snode) Raised if a node in the source graph has no associated chain. exceptions.ChainOverlapError(tnode, snode0, …) Raised if two source nodes have an overlapping chain. exceptions.DisconnectedChainError(snode) Raised if a chain is not connected in the target graph. exceptions.InvalidNodeError(snode, tnode) Raised if a chain contains a node not in the target graph. exceptions.MissingEdgeError(snode0, snode1) Raised when two source nodes sharing an edge to not have a corresponding edge between their chains.